package com.fingard.util;


import org.apache.xmlbeans.impl.util.Base64;

import com.fingard.io.FileHelper;

import javax.crypto.Cipher;

import java.io.*;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

/**
 * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 * </p>
 * @author ***
 *
 */
public class RSAUtil {

    /** *//**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /** *//**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /** *//**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /** *//**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /** *//**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /** *//**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String pubkeyStr = new String(Base64.encode(publicKey.getEncoded()));
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        String prikeyStr = new String(Base64.encode(privateKey.getEncoded()));
        String cer = "E:\\rsa"+ File.separator+"pub.cer";
        String key = "E:\\rsa"+ File.separator+"pri.key";
        System.out.println("privateKey = [" + prikeyStr + "]");
        FileHelper.writeFile(cer, pubkeyStr, "gbk");
        System.out.println("publicKey = [" + pubkeyStr + "]");
        FileHelper.writeFile(key, prikeyStr, "gbk");

        Map<String, Object> keyMap = new HashMap<String, Object>(2);

        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /**
     * 获取私钥
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return new String(Base64.encode(key.getEncoded()));
    }

    /**
     * 获取公钥
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return new String(Base64.encode(key.getEncoded()));
    }


    /**
     * 公钥加密
     * @param data
     * @param publicKey
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(publicKey.getBytes());
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * 公钥加密
     * @param plainTextData
     * @param charsetName
     * @param publicKey
     * @return
     * @throws Exception
     */
    public static String encryptByPublicKey(String plainTextData,String charsetName, String publicKey)
            throws Exception {
        byte[] data = plainTextData.getBytes(charsetName);
        byte[] encryptedData = encryptByPublicKey(data,publicKey);
        return new String(Base64.encode(encryptedData),charsetName);
    }


    /**
     * 私钥解密
     * @param data
     * @param privateKey
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(privateKey.getBytes());
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * 私钥解密
     * @param encryptedData
     * @param charsetName
     * @param privateKey
     * @return
     * @throws Exception
     */
    public static String decryptByPrivateKey(String encryptedData,String charsetName, String privateKey)
            throws Exception {
        byte[] data = Base64.decode(encryptedData.getBytes(charsetName));
        byte[] decryptedData = decryptByPrivateKey(data,privateKey);
        return new String(decryptedData,charsetName);
    }

    /**
     * 私钥加密
     * @param data
     * @param privateKey
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(privateKey.getBytes());
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * 私钥加密
     * @param plainTextData
     * @param charsetName
     * @param privateKey
     * @return
     * @throws Exception
     */
    public static String encryptByPrivateKey(String plainTextData,String charsetName, String privateKey)
            throws Exception {
        byte[] data = plainTextData.getBytes(charsetName);
        byte[] encryptedData = encryptByPrivateKey(data,privateKey);
        return new String(Base64.encode(encryptedData),charsetName);
    }


    /**
     * 公钥解密
     * @param data
     * @param publicKey
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(publicKey.getBytes());
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * 公钥解密
     * @param encryptedData
     * @param charsetName
     * @param publicKey
     * @return
     * @throws Exception
     */
    public static String decryptByPublicKey(String encryptedData,String charsetName, String publicKey)
            throws Exception {
        byte[] data = Base64.decode(encryptedData.getBytes(charsetName));
        byte[] decryptedData = decryptByPublicKey(data,publicKey);
        return new String(decryptedData,charsetName);
    }

    /**
     *
     * @param path
     * @return
     * @throws Exception
     */
    public static String loadKeyByFile(String path) throws Exception {
        try {
            BufferedReader br = new BufferedReader(new FileReader(path));
            String readLine = null;
            StringBuilder sb = new StringBuilder();
            while ((readLine = br.readLine()) != null) {
                sb.append(readLine);
            }
            br.close();
            return sb.toString();
        } catch (IOException e) {
            throw new Exception("数据读取错误");
        } catch (NullPointerException e) {
            throw new Exception("输入流为空");
        }
    }


    public static void main(String[] args) throws Exception{
//        Map<String,Object> map = genKeyPair();
        String text = "陈超1993chenchao";
        System.out.println("原文------------");
        System.out.println(text);
        System.out.println("原文------------");
//        String prikeyStr =new String(Base64.encode(((RSAPrivateKey)map.get(PRIVATE_KEY)).getEncoded()));
        String prikeyStr =loadKeyByFile("E:\\rsa\\pri.key");
        byte[] encryptedData =  RSAUtil.encryptByPrivateKey(text.getBytes("gbk"),prikeyStr);
        String encryptedStr = new String(Base64.encode(encryptedData));
        System.out.println("加密后----------------");
        System.out.println(encryptedStr);
        System.out.println("bPhQuMp2gaTRtusg6e1hVNjWjMb1mJ0+JSxE4htjdzMJyr+LT/ssaOXmesnMgoxfKWtCs2tz9D6Okn7VpGaBucGShYsnKX2626/bIGQLL7FWsWdBmDk6+yeGu0pJ6zUshgVhQMJG/1AXbAHF5rwba4L+x5AISevhd8ndcpfJA5Q=\n");
        System.out.println("加密后----------------");

        byte[] decryptedDate = Base64.decode(encryptedStr.getBytes());
//        String pubkeyStr =new String(Base64.encode(((RSAPublicKey)map.get(PUBLIC_KEY)).getEncoded()));
        String pubkeyStr =loadKeyByFile("E:\\rsa\\pub.cer");
        String decryptedStr = new String(RSAUtil.decryptByPublicKey(decryptedDate,pubkeyStr),"gbk");

        System.out.println("解密后----------------");
        System.out.println(decryptedStr);
        System.out.println("解密后----------------");

    }
}

